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AIRCRAFT AND TECHNOLOGY CONCEPTS FOR AN N+3 SUBSONIC TRANSPORT

MIT, Aurora Flights Science, and Pratt & Whitney

Elena de la Rosa Blanco May 27, 2010

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Message •  Defined documented scenario and aircraft requirements •  Created two conceptual aircraft: D (double-bubble) Series and H (Hybrid

Wing Body) Series

–  D Series for domestic size meets fuel burn, LTO NOx, and balanced field length N+3 goals, provides significant step change in noise

–  H Series for international size meets LTO NOx and balanced field length N+3 goals

–  D Series aircraft configuration with current levels of technology can provide major benefits

•  Developed first-principles methodology to simultaneously optimize airframe, engine, and operations

•  Generated risk assessment and technology roadmaps for configurations and enabling technologies

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Project Enabled by University-Industry Collaboration •  MIT

–  (GTL) Propulsion, noise, (ACDL) aircraft configurations, systems, (ICAT) air transportation, and (PARTNER) aircraft-environment interaction

–  Student engagement (education)

•  Aurora Flight Sciences –  Aircraft components and subsystem technology; Aerostructures and

manufacturing; System integration

•  Pratt & Whitney –  Propulsion; System integration assessment

•  Collaboration and teaming –  Assessment of fundamental limits on aircraft and engine performance –  Seamless teaming within organizations AND between organizations

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N+1

N+2

N+3

NASA System Level Metrics …. technology for dramatically improving noise, emissions, performance

*** Technology readiness level for key technologies = 4-6

** Additional gains may be possible through operational improvements

* Concepts that enable optimal use of runways at multiple airports within the metropolitan area

•  Energy intensity metric for comparison of fuel burn •  Add a climate impact metric for evaluation of the aircraft

performance –  Global temperature change as a result of the emissions

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Three Major Results from N+3 Program

•  Development and assessment of two aircraft configurations:

–  D Series for domestic size meets fuel burn, LTO NOx, and balanced field length N+3 goals, provides significant step change in noise

–  H Series for international size meets LTO NOx and balanced field length N+3 goals

•  Comparison of D Series and H Series for different missions (domestic and international)

•  Trade study identification of D Series benefits from configuration vs. advanced technologies

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Fuel burn (kJ/kg-km)

Noise Field length

LTO NOx

100% of N+3 goal

Fuel burn (kJ/kg-km)

100% of N+3 goal

Noise

LTO NOx

Field length

Two Scenario-Driven Configurations Double-Bubble (D series):

modified tube and wing with lifting body Hybrid Wing Body (H series)

Baseline: B737-800 Domestic size

Baseline: B777-200LR International size

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Baseline H Series D Series

Domestic International

N+3 Goal

D and H Series Fuel Burn for Different Missions

•  D Series has better performance than H Series for missions examined •  H Series performance improves at international size

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8

PFEI for 50 Best Existing Aircraft within Global Fleet Computed using Piano-X software

D8.5

Fuel Burn Baselines and Results

H3.2

9

-60 -50 -40 -30 -20 -10 0

%60 %50 %40 %30 %20 %10 %0

D8 configuration

2035 Engine Technology

Airframe load reduction

Approach operations

LDI combustor

Natural laminar flow on bottom wing

Airframe materials/processes

EPNdB Noise reduction relative to Stage 4

Fuel burn

Noise

LTO NOx

Balanced Field Length for all designs = 5000 feet

% Fuel burn reduction relative to baseline % LT NOx reduction relative to CAEP6

D Series Configuration is a Key Innovation

Fuel Burn (kJ/kg-km)

Noise (EPNdB below Stage 4)

Field Length (feet)

LTO NOx (g/kN) (% below CAEP 6)

D8.1 (Aluminum)

D8.5 (Composite)

D8 Configurations: Design and Performance

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D8 – Double Bubble Configuration with current technologies

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•  Double bubble lifting fuselage with pi-tail

•  Engines flush-mounted at aft fuselage with boundary layer ingestion; engine noise shielding and extended rearward liners

•  Reduced cruise Mach number with unswept wings and optimized cruise altitude

•  Eliminates slats

•  BFL = 5000 feet

Payload: 180 PAX Range = 3000 nm

Advanced Structural Materials Health and

Usage Monitoring

Active Load Alleviation

Boundary Layer Ingestion

Operations Modifications: -  Reduced Cruise Mach:0.72 for D8.1 and 0.74 for D8.5 -  Optimized Cruise Altitude: 40,000 ft. for D8.1 and 45,000 ft. for D8.5 -  Descent angle of 4º -  Approach Runway Displacement Threshold

Natural Laminar Flow on Wing

Bottom

Faired Undercarriage

Lifting Body with pi-tail

Reduced Secondary

Structure weight

D8.5 Airframe Technology Overview

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Distortion Tolerant Fan

LDI Advanced Combustor

Tt4 Materials and advanced cooling

High Bypass Ratio Engines (BPR=20)

with high efficiency small cores

Advanced Engine Materials Variable Area Nozzle

D8.5 Engine Technology Overview

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Multi-segment rearward acoustic liners

Design Modification Sequence from B737-800 to D8.1 and D8.5

•  Case 0: B737-800 •  Case 1: Optimized B737-800 •  Case 2: Fuselage replacement from tube+wing to double bubble •  Case 3: Reduced cruise Mach number from 0.8 to 0.72 •  Case 4: Engines flush-mounted on top, rear fuselage •  Case 5: 2010 Engine technology •  Case 6: Slats elimination

•  Case 7 (D8.1): Balanced Field Length reduced from 8000 ft. to 5000 ft. •  Case 8: Faired Undercarriage •  Case 9: 2035 Engine technology •  Case 10: Advanced Airframe materials and processes •  Case 11: Natural laminar flow on bottom wing •  Case 12: Airframe loads reduction •  Case 13: Approach operations

•  Case 14 (D8.5): LDI combustor 14

Fuel burn evolution from B737-800 to D8.1 and D8.5

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B73

7-80

0 M

=0.8

B73

7-80

0 op

timiz

ed

Dou

ble-

bubb

le fu

sela

ge

Slow

to M

=0.7

2

Eng

rear

2010

Eng

. Te

ch,

BFL

=500

0 ft

100%

96%

77%

71%

39% 33% 30%

55% 51% 50%

51%

29%

2035

eng

ine

tech

.

Airf

ram

e m

ater

ials

/pro

cess

es

NLF

on

botto

m w

ing

Load

redu

ctio

n

D8.5 D8.1

Slat

s re

mov

e

Faire

d un

derc

arria

ge

16

B73

7-80

0 M

=0.8

B73

7-80

0 op

timiz

ed

Dou

ble-

bubb

le fu

sela

ge

Slow

to M

=0.7

2

Eng

rear

2010

Eng

ine

Tech

.

Slat

s re

mov

al

BFL

=500

0 ft

63%

47%

44%

44%

27% 27%

40% 38%

36%

13%

2035

eng

ine

tech

.

Airf

ram

e m

ater

ials

/pr

oces

ses

NLF

on

botto

m

win

g

Load

redu

ctio

n

47%

57%

LDI c

om.

D8.1

D8.5

LTO NOx evolution from B737-800 to D8.1 and D8.5

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App

roac

h op

s.

Stag

e 4

limit

B73

7-80

0 op

timiz

ed

Dou

ble-

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Slow

to M

=0.7

2

Eng

rear

with

201

0 te

ch.

Exte

nded

rear

war

d lin

ers

Slat

s re

mov

al

BFL

=500

0 ft

0 3

-3.5

-20.2 -25.7

-31.9

2035

eng

ine

tech

.

Airf

ram

e m

ater

ials

/pro

cess

es

NLF

on

botto

m w

ing

Load

redu

ctio

n

-38

1.9

-48.1

-53.9 -54.6 -55.1 -60

D8.5 D8.1

Noise evolution from B737-800 to D8.1 and D8.5

-38.7

Faire

d un

derc

arria

ge

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B737 ➡ D8 Study–Main Observations

•  Improvement arises from integration and exploitation of indirect benefits – there is no one “magic bullet”

•  Design methodology allows exploration of interactions

•  D8 fuselage alone is slightly draggier than B737's, but enables…

–  lighter wing

–  smaller lighter tails

–  enables fuselage BLI

–  smaller, lighter engines

–  shorter, lighter landing gear

–  … etc

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•  Entire upper fuselage BL ingested

•  Exploits natural aft fuselage static pressure field

–  Fuselage's potential flow has local M = 0.6 at fan face

–  No additional required diffusion into fan

–  No generation of streamwise vorticity

–  Distortion is a smoothly stratified total pressure

Contoured aft fuselage

Engines ingesting full upper surface boundary layer

D8 BLI Approach

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•  Climate change impact. D8 results on over 80% climate improvement from B737-800

•  Improved Load/Unload Time. D8.5 provides reduction in block time during load and unload and approach operations

•  Airport capacity. D8 could allow for increased airport capacity due to wake vortex strength reduction

B737-800 30 x 6 per aisle

(35 min. load, unload) D8.5

23 x 4 per aisle (20 min. load, unload)

Flighttime(hr) Triptime(hr)

B737 D8.5 B737 D8.5

NYC‐LAX 4.81 5.29 5.98 5.96 (D8.5is1minutefasterthanB737)

NYC‐ORD 1.55 1.73 2.71 2.40 (D8.5is19minutesfasterthanB737)

BOS‐DCA 0.93 1.06 2.09 1.73 (D8.5is22minutesfasterthanB737)

Improved Load/Unload Time and Airport Capacity

First principle innovative aircraft design optimization tool (M. Drela)

TASOPT (Transport Aircraft System OPTimization)

•  Modelled on a first-principles basis, NOT from correlations

•  Simultaneously optimizes airframe, engine, and operations parameters for given mission

•  Developed in modules so easily integrated with other tools

•  Generate required output files for detailed aeroelastic and aerodynamic analysis

•  Allows aircraft optimization with constraints on noise, balanced field length, and other environmental parameters

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Summary

•  Established documented scenario and aircraft requirements

•  Created two conceptual aircraft: D (double-bubble) Series and H (Hybrid Wing Body) Series

–  D Series for domestic size meets fuel burn, LTO NOx, and balanced field length N+3 goals, provides significant step change in noise

–  H Series for international size meets LTO NOx and balanced field length goals

–  D Series aircraft configuration with current levels of technology can provide major benefits

•  First-principles methodology developed to simultaneously optimize airframe, engine, and operations

•  Generated risk assessment and technology roadmaps for configurations and enabling technologies

Elena de la Rosa Blanco (edlrosab@mit.edu) Link to presentation: http://www.nasa.gov/topics/aeronautics/features/future_airplanes.html